1. Field of the Invention
The present invention relates to transmission and more particularly to an improved transmission system of an eyebrow-beautifying device.
2. Description of Related Art
A conventional transmission system of an eyebrow-beautifying device comprises a transmission member pivotably provided on a bracket on a motor. One end of the transmission member is driven by the motor so that the transmission member can operate by leverage. A link of needle is coupled to the other end of the transmission member. As such, the link of needle can move reciprocally, linearly by the action of cam. Thus, a used needle is required to remove prior to inserting a new one for replacement in such cam design. An insertion force of the needle will transmit to the transmission member directly. However, the transmission member is merely supported by a small fulcrum. Hence, it is possible that a bending torque can be created if the force is not balanced or excessively large. As an end, the transmission member is susceptible of damage. In another aspect, the transmission member or any of other components is typically formed of plastic for reducing the load of the motor. This can further tend to bend or even greatly wear the transmission member. Moreover, a distance from one end of the transmission member to the fulcrum and another distance from the other end to the fulcrum are different. Hence, torque is imbalance. Both ends of the transmission member may increase as the distances increase while the transmission member is operating by leverage when the motor is rotating. This in turn can cause excessive vibration of the motor, resulting in a reduction of motor output power and greatly wearing the transmission system.
A Taiwanese Patent Published No. 111,055 entitled “Improved Eyebrow-Beatifying Device” disclosed, as shown in FIGS. 2 to 5 thereof, a motor shaft 41 having an oblique top surface 42, an action block 6 supported on the oblique surface, and a link of needle 8 linearly, reciprocally moveable by means of frictional surface contact between the action block 6. Another Taiwanese Patent Published No. 160,146 entitled “Improved Transmission System of Eyebrow-Beatifying Device” disclosed, as shown in FIG. 1 thereof, a motor shaft 12 having an oblique top surface and an action block 13 supported on the oblique surface. Moreover, the linear movement by means of frictional surface contact as disclosed in Taiwanese Patent Published No. 111,055 is changed as a frictional line contact between the action block 13 and the oblique surface of the motor shaft 12. As an end, a link of needle 16 is able to move linearly, reciprocally.
Both Taiwanese Patents have contributed to the transmission system of eyebrow-beautifying device. However, both prior art still suffered from several disadvantages. For example, with respect to the transmission system of eyebrow-beautifying device, both disclosed an elongate transmission bar projected from the action block, and a link of needle coupled to the transmission bar. As such, the action block will operate by leverage for enabling the link of needle to move linearly, reciprocally when a frictional surface contact between the action block and the oblique surface of the motor shaft is carried out. As best seen from its figures, torque of the action block is much less than that between the transmission bar and the link of needle. Typically, torque between the transmission bar and the link of needle is about 2 to about 3 times larger than that of the action block. As such, for example, 0.1 m/m error between the action block and the oblique surface of the motor shaft due to wear will cause about 0.2 m/m to 0.3 m/m or larger error in the moving distance of the link of needle. As a consequence, a number of disadvantages are found such as abnormal vibration during operation, lowering mechanical efficiency, excessive wear of components, and shortening of useful life of the transmission system.
With respect to the transmission system of eyebrow-beautifying device, both disclosed an elongate transmission bar projected from the action block, and a link of needle coupled to the transmission bar. But there is no support under the transmission bar. Thus, a used needle is required to remove prior to inserting a new one for replacement. But an insertion force of the needle will transmit to the transmission bar directly. Hence, the transmission bar tends to be deformed or even broken (i.e., shortened useful life) after a short period of time of operation. Moreover, abnormal vibration during operation and lowering mechanical efficiency of the transmission system are found. In another aspect, the transmission member or any of other components is typically formed of plastic for reducing the load of the motor. This can further tend to bend and greatly wear the transmission member or even damage other adjacent, coupled components. Thus, the need for improvement still exists.